"Calling something" it is now yours. You can summon anything funny. and you can something anything just all out embarrassing. Example: "Summon her being obsessed with Zoo Tycoon" see its just weird. A hard summon is just an even greater summon. Credit is given to IH for speading it around cincinnati. Summon is just all around fun to say. so start summoning the chess club or maybe just the average nerd.

In World of Warcraft, is when you call upon your allies to assist you in pwning evil beasties of all sorts.
In real life however, is when you seduce a person, with a come-hither expression and demeanor used to pull the person in so that you can hug, snog, whatever it is you do once you seduce someone.